I really do think the whole GHD hype is getting a bit much.
Yes, they ARE great straighteners. And a few years ago, they were most certainly the best, as most others either weren't ceramic or were much poorer quality. But many manufacturers seem to have caught up with GHDs quality wise and produce items that work just as well.
There are still some rubbish ones out there, but it is possible to buy some "mid price" ones that are still excellent. I've had both GHDs (that eventually blew up just out of guarantee!) and Remingtons and Coriolis ones that all gave excellent results. Got short hair now though, so I don't use them much other than on the front.
£150 for a pair of straighteners is a daft price to pay. GHDs are good...but not THAT good.